Chronic lung disease (also called CLD or bronchopulmonary dysplasia) - a term for long-term respiratory problems in premature babies that results from lung injury from treatments with mechanical ventilators and oxygen.

Continuous positive airway pressure (CPAP) - air or oxygen delivered to the lungs under a small amount of pressure through an endotracheal tube or nasal prongs.

Cytomegalovirus (CMV) - a virus related to the herpes virus group of infections.

Respiratory distress syndrome (also called RDS, hyaline membrane disease, or HMD) - a condition of premature infant lungs due to insufficient surfactant, a substance in the lungs that helps the air sacs stay open.

Respiratory syncytial virus (RSV) - an infection that causes inflammation of the lower airways and pneumonia.

Retinopathy of prematurity (ROP) - a disorder of the blood vessels of the retina (the light sensitive part of the eye) that is common in premature babies.